Ballast cut-out for electric lamps.



No. 685,487. I Patented Oct. 29, I90l.

' H. N. POTTER. v

BALLAST CUT-OUT FOR ELECTRIC LAMPS.

(Application filed m 14, 19005 (No Model.)

WITNESSES: INVENTOR M m 6 %@M4W V 7 ATTORNEY.

UNITED STATES PATENT OFFICE.

HENRY NOEL POTTERfOF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO GEORGE WESTINGHOUSE, OF PITTSBURG, PENNSYLVANIA.

BALLAST CUT-OUT FOR ELECTRIC LAMPS.

SPEGIFIATION forming part of Letters Patent No. as 5,457, dated October 29, 1901.

Application filed July 14, 1900. berial No. 23,650. (No model.) i

To (0% whom it may concern.-

Be it known that I, HENRY NOEL POTTER, a citizen of the United States,-residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Ballast Out-Outs for Electric Lamps, of which the following is a specification.

My invention relates to electric lamps of the type in which the light-giving body or glower is a conductor of electricity only when hot; and it has for its object to provide an automaticallyoperating means for cutting out the ballast-conductor when the voltage of the line supplying the lamp exceeds a predetermined limit of safety for such ballast-conductor.

With these ends in view I have devised the means shown in the accompanying drawings, in which Figures 1 and 2 are diagrams of the oper ating parts of a lamp and the circuitsof the same, the circuit connections in the two figures being different in certain particulars. Fig. 3 is a diagram of a lamp-glower, its ballast and circuits involving a constructionin which the ballast-wire serves to cut itself out of circuit. Fig. 4 is a view similar to Fig. 3 of a modification in which the ballast cut-out is controlled directly by the ballast wire. Fig. 5 is a diagram of a lamp having a plurality of glowers and provided with a modified form of electromagnetic cut-out.

It is well known that if the voltage of the line supplying electric lamps of the character above indicated materially exceeds that for which the ballast devices are designed destruction of the ballast-wire or the glower is liable to occur. It may not be possible to determine in all cases whether the ballast or the glower will be more readily and inexpensively replaced if destroyed; but as the life of the glower is necessarily limited, whereas the ballast, if properly constructed and used, should last indefinitely, and whereas the glower is in general more easily replaced than the ballast, the'destruction of the glower will in general cause less disturbance than the destruction of the ballast. It is in view of these considerations that I have devised the means shown in the drawings for short-circuiting the ballast-conductor of the lamp when an abnormal increase of voltage on the line causes a dangerous excess of-current through the ballast and the glower or glowers.

Referring now particularly to Fig. l of the drawings, one terminal of the glower 1 and the corresponding terminal of the heater 2 are connected to the line-wire 3 by means of a conductor 4, as is usual in lamps of this character. The other terminal of the glower is connected to one terminal of the ballast-wire 5 by means of a conductor 6, the other terminal of the ballast-wire being connected to one terminal of a cut-out coil 7, the other terminal of said coil being connected to a terminal block 8, which in turn is connected to the line conductor 9 by means of a wire 10. Fastened to the terminal block 8 is one end of a conducting strip or ribbon 11, having at its free end a suitable contact device 12 and connected at its intermediate point to the movablecore 13 of the cut-out coil'7. The contact device 12 is located between two terminal pieces 1 1 and 15, the terminal piece 15 being connected by conductor 16 to one end of the coil 2 and the piece 14 being connected by a conductor 17 to the conductor 6, leading from one end of the glower to the ballast-wire 5. When the current is first supplied from the line to the lamp, the contact 12 is in engagement with the terminal piece 15, it being held in that position by the weight of the core 13. The circuit is thus completed through the heater coil and is maintained until the temperature of the glower is raised to the conducting-point,when the current will traverse the glower, ballastresistance 5, cut-out coil 7, and thus effect the lifting of the core 13, so as to interrupt the heater-circuit. The several parts should be so designed and constructed that anormal voltage will not be sufficient to raise the core 13 to the point where the contact 12 will engage with the terminal piece 14. In case the voltage increases materially beyond the normal the strip 11 will be deflected sufficiently to bring thecontact 12 into engagement with the piece 14. When this takes place, the ballast-wire 5 and the coil 7 will be short-circuitcd by means of the conductor 17, the piece 14, the strip 11, block 8, and conductor 10.

It is obvious that as soon as this short-circuiting takes place the action of gravity will serve to break the short circuit, since the coil 7, as well as the ballast device, is short-circuited. If the excessive voltage is maintained, the short-circuiting action will be repeated, and these vibrations of the strip 11 will continue until the voltage returns to the normal or until the glower is destroyed.

Referring now to Fig. 2, the several parts are the same in construction as those shown in Fig. 1, except as will be specifically pointed out, and as the same reference-numerals are employed the description heretofore given may be read in connection with both figures.

In Fig. 2 the glower-terminal, which is inpendent of the corresponing heater-terminal, is connected to one terminal of the cut-out coil 7 by means of a conductor 18, the other terminal of the cut-out coil being connected by a wire 19 to one terminal of the ballastwire 5. The other terminal of the ballastwire is connected by a wire 20 to the terminal block 8. \Vith this arrangement of circuits an excessive voltage will serve to bring the contact 12 into engagement with the terminal piece 14, as in the operation already described; but the short circuit thus established will be through the wire 18, the coil 7, conductor 17, piece 14, contact 12, and strip 11, and therefore, as will be readily understood, the cut-out coil will serve to maintain this short circuit continuously so long as the glower remains intact. WVhen the glower is destroyed, the core 13 will obviously be released and will return to its normal position.

Referring now to Fig. 3, the ballast-wire, connected in series with the glower 1, is shown as comprising two lengths 5" and 5 of iron wire, the inner ends of the lengths being supported upon a bar 21, that may be pivoted at an intermediate point, as indicated, if desired, the outer end of the length 5 being permanently attached to the leading-in wire, as is usual. The corresponding end of the length 5 is attached to one end of a rockerarm 22, the pivotal support of this arm being at the extremity of the other leading-in wire. The several parts will be so constructed and arranged that when an excessive voltage effects an abnormal heating of the lengths of ballast-wire their expansion will serve to rock the arm 22, so as to bring its one end into engagement with the contact-point at the outer end of the length 5 and thus establish a short circuit.

In Fig. 4 the lengths 5 and 5 of the ballastwire are attached at their corresponding ends to adjacent but normally non-engaging ends of two spring-arms 23, these arms being normally held by the ballastwires under tension against a tendency to spread apart. When the lengths of ballast-wire become heated abnormally by reason of an excessive voltage on the line, their expansion will permit the arms 23 to spread apart and thus bring their adjacent free ends into contact at 24., and thus establish a short circuit around the ballast.

In Fig. 5 two glowers 1 and 1 are shown as connected and arranged so as to be raised to conducting temperature by the heater 2 and are severally provided with ballast-resistances 5 and 5 The current is supplied primarily to the heater and subsequently to the glowers through conductors 4 and 10, and the cut-out device 25 is employed solely for interrupting the heater-circuit when the glowers become conductive. The cut-out 27 for the ballast-conductors serves to open-circuit the lamp when the voltage becomes excessive, since the magnet-coil 28, which serves to actuate the movable member29 of the cutout, is connected in circuit directly across from conductor 4; to conductor 10. A re= sistance 30 is connected in series with the coil 28 in order to prevent a short-circuiting action so long as the voltage remains normal, this resistance of course being properly designed to provide for this operation.

\Vhile I have shown and described several devices and arrangements of circuits whereby the ballast-wires may be protected from destruction or injury in case of excessive voltages, I desire it to be understood that my invention is not limited to such details, since other forms of devices which will effect the same result may be employed by any one skilled in the art without departing from the spirit and scope of my invention.

I claim as my invention- 1. In an electric lamp of the type described, the combination with a glower and a ballast device therefor, of means for short-circuiting the ballast device when the line-voltage exceeds a predetermined limit.

2. In an electric lamp of the type described, the combination with a glower and a ballast therefor, of means actuated by an excessive voltage to divert the glower-current from the ballast device.

3. In an electric lamp of the type described, the combination with a glower and a ballastresistance therefor, of means operated by voltage in excess of a predetermined limit for diverting the glower-current from the ballastresistance, such means being actuated by the heating effect produced upon the resistance by the excessive voltage.

In testimony whereof Ihave hereunto subscribed my name this 7th day of July, 1900.

HENRY NOEL POTTER.

\Vitnesses:

MURRAY (J. BEEBE, HUGH A. Oaooxs.

ICC 

